摘要: A disadvantage of the MLS approximation is that the shape function of this method does not satisfy the property of Kronecker Delta function. Thus developing an interpolating MLS approximation is very important. In this paper, the interpolating moving least-squares (IMLS) method presented by Lancaster and Salkauskas is discussed in detail and a simplified expression of the approximation function of the IMLS method is given. The simpler expression makes it more convenient to use this method. The error estimate of the approximation function also is discussed. And a numerical example is given to confirm the results.
摘要: Based on the MLS approximation, a meshless method for the numerical solution of the generalized Burger’s equation is presented in this paper. The nonlinear discrete scheme of the generalized equation is obtained, and is solved with the method of iteration. Compared with numerical methods based on mesh, the meshless method needs only the scattered nodes instead of meshing the domain of the problem. An example is given to demonstrate the accuracy of the proposed method. The numerical results agree well with the exact solutions.
摘要: Based on the characteristics and the common massage manipulations of Chinese medical massage, a practical series mechanical arm was presented to act the manipulations with the parallel executive mechanism. Forward kinematics was solved by the Denavit-Hartenberg transformation after the kinematics model of the arm was established. And the three-dimensional model of the arm was created by Pro/E and was imported into ADAMS for the kinematics analysis. The results indicated that the common massage manipulations could be simulated by the arm correctly and flexibly, and it verified the accuracy of the mechanism design of the arm.
摘要: This paper introduces the dynamics model and mathematical characteristics of the constant difference of overflowing pressure with computerized simulation by power bond graph of the fixed differential relief valve hydraulic system on simplified vertical planetary internal grinder, which puts forth proposals to design hydraulic circuit or component. Simulation shows that, when the load changes more than 50%, the speed of cylinder piston changes less than 0.31%, and the efficiency of the hydraulic system has also been greatly improved, which matches the experiments. It makes certain reference to the design of the hydraulic system in which the load changes large.
摘要: In this paper, a two-machine two-stage flow shop with identical jobs is considered. Each of identical jobs has two tasks. The first task can be processed on either machine, called flexible task, while the second task must be processed on the second machine and can't be processed unless the first task has been processed. The problem is to determine the assignment of the flexible tasks to the machines for each job, with the objective of maximizing the throughput rate. This model is applied to the graphic programs processing which comprises data processing and graphics processing. We consider three cases regarding the capacity of the buffer between the machines with infinite number of jobs. We present optimal algorithm for each variant of the problem.
摘要: With the issue of environmental pollution and energy crisis worsening day by day, the researches and applications of low-pollution and high energy-efficient electric vehicles have become the research trend in the automotive area nowadays. On the basis of analyzing the requirements of pure electric vehicles’ drive motors and power batteries, this paper makes a reasonable selection of the basic parts’ type of pure electric vehicles’ powertrain and the parameters matched. The matching parameter is proved to be reasonable by simulation.
摘要: A discrete element numerical model simulating the process of gas pressurization in coalbed methane wells is built based on UDEC software. The model considers the unique vertical fracture system of the coal. Simulates the distribution of effective stress, pore pressure and the node displacement vector around the wellbore in the process of pressurization under different terrestrial stress conditions. The analysis shows that, reservoir fluid flow and matrix deformation in the pressurization of cavity completion can be better represented by taking coal's unique fracture system into consideration. Coal reservoir with anisotropic stress is more prone to rupture and collapse than that under isotropic condition. In the vertical fracture system, the discrepancy of the fluid velocity will lead to differences in formation stress gradient and help generate shearing fracture. Tensile fractures’ formation and growing trend can be reflected by nodal displacement vector distribution.
摘要: To study the kinematic characteristics of a new designed flange vertical lathe with double machining tools, a virtual prototype model was developed in ADAMS with the help of PRO/E and MechPro, a seamless interface program between both mentioned software. And kinematic and dynamic simulations were carried out. The results of the simulations are consistent with the reality which states that the model was created correctly and the simulations were reliable.
摘要: With the development of manufacturing industry, the stroke speed of stamping machine is higher and higher. In accordance with the development, researchers and engineers have paid more and more attention to developing various types of ultra high speed stamping machines. The key to develop ultra high speed stamping machine is to solve the problem of inertia equilibrium. This paper presents an optimization approach for multi-objective inertia equilibrium design for ultra high speed stamping machine. Simulation results demonstrate the effectiveness of the proposed approach.
摘要: Cutting transport is a big problem in a wellbore in deep-water drilling specially with a long and large diameter riser. And proper cutting concentration is the key parameter of controlling wellbore pressure and ECD. In this study, a cutting concentration model of a vertical wellbore annulus in deep-water drilling operation has been developed. The model is solved numerically to predict the proportion respectively in each interval of the deep-water well and the rule of proportion changed with time. It is applied in the calculation of cutting concentration in the oil field and a good effect has been achieved.